import {Message} from 'element-ui';
import path from 'path';
export async function generateTheme (val, oldVal, ORIGINAL_THEME, version, chalk, changeChalk) {
  if (typeof val !== 'string') return;
  const themeCluster = getThemeCluster(val.replace('#', ''));
  const originalCluster = getThemeCluster(oldVal.replace('#', ''));
  // console.log(themeCluster, originalCluster)

  const $message = Message({
    message: '  编译主题中...',
    customClass: 'theme-message',
    type: 'success',
    duration: 3000,
    showClose: true,
    iconClass: 'el-icon-loading'
  });

  const getHandler = (variable, id) => {
    return () => {
      const originalCluster = getThemeCluster(ORIGINAL_THEME.replace('#', ''));
      const newStyle = updateStyle(chalk, originalCluster, themeCluster);

      let styleTag = document.getElementById(id);
      if (!styleTag) {
        styleTag = document.createElement('style');
        styleTag.setAttribute('id', id);
        document.head.appendChild(styleTag);
      }
      styleTag.innerText = newStyle;
    };
  };

  if (!chalk) {
    const url = path.resolve('/static/theme/index.css');
    // const url = `https://unpkg.com/element-ui@${version}/lib/theme-chalk/index.css`
    await getCSSString(url, 'chalk', function (cha) {
      chalk = cha;
      changeChalk(chalk);
    });
  }

  const chalkHandler = getHandler('chalk', 'chalk-style');

  chalkHandler();

  const styles = [].slice.call(document.querySelectorAll('style'))
    .filter(style => {
      const text = style.innerText;
      return new RegExp(oldVal, 'i').test(text) && !/Chalk Variables/.test(text);
    });
  styles.forEach(style => {
    const { innerText } = style;
    if (typeof innerText !== 'string') return;
    style.innerText = updateStyle(innerText, originalCluster, themeCluster);
  });
  $message.close();
}

export function updateStyle (style, oldCluster, newCluster) {
  let newStyle = style;
  oldCluster.forEach((color, index) => {
    newStyle = newStyle.replace(new RegExp(color, 'ig'), newCluster[index]);
  });
  return newStyle;
}

export function getCSSString (url, variable, changeChalk) {
  return new Promise(resolve => {
    const xhr = new XMLHttpRequest();
    xhr.onreadystatechange = () => {
      if (xhr.readyState === 4 && xhr.status === 200) {
        let resp = xhr.responseText.replace(/@font-face{[^}]+}/, '');
        changeChalk(resp);
        resolve();
      }
    };
    xhr.open('GET', url);
    xhr.send();
  });
}

export function getThemeCluster (theme) {
  const tintColor = (color, tint) => {
    let red = parseInt(color.slice(0, 2), 16);
    let green = parseInt(color.slice(2, 4), 16);
    let blue = parseInt(color.slice(4, 6), 16);

    if (tint === 0) { // when primary color is in its rgb space
      return [red, green, blue].join(',');
    } else {
      red += Math.round(tint * (255 - red));
      green += Math.round(tint * (255 - green));
      blue += Math.round(tint * (255 - blue));

      red = red.toString(16);
      green = green.toString(16);
      blue = blue.toString(16);

      return `#${red}${green}${blue}`;
    }
  };

  const shadeColor = (color, shade) => {
    let red = parseInt(color.slice(0, 2), 16);
    let green = parseInt(color.slice(2, 4), 16);
    let blue = parseInt(color.slice(4, 6), 16);

    red = Math.round((1 - shade) * red);
    green = Math.round((1 - shade) * green);
    blue = Math.round((1 - shade) * blue);

    red = red.toString(16);
    green = green.toString(16);
    blue = blue.toString(16);

    return `#${red}${green}${blue}`;
  };

  const clusters = [theme];
  for (let i = 0; i <= 9; i++) {
    clusters.push(tintColor(theme, Number((i / 10).toFixed(2))));
  }
  clusters.push(shadeColor(theme, 0.1));
  return clusters;
}
